Post-Traumatic Stress Disorder (PTSD) has been an officially recognized illness since 1980 and it may be defined as the development of significant anxiety, fear, helplessness and horror after exposure (experienced or witness) to trauma, defined as an event associated with either actual or threatened death or injury to oneself or another. Individuals experience associated symptoms of detachment and loss of emotional responsively. The patient may feel de-personalized and unable to recall specific aspects of the trauma, though typically it is re-experienced through intrusions in thoughts, dreams, or flashbacks, particularly when cues of the original event are present. They are crippled by nightmares, outbursts of anger and hyper-vigilance and arousal, and constantly on the lookout for danger. Some try not to think about it, or avoid anyone who reminds them of the trauma. They can become withdrawn and so emotionally & psychologically numb they no longer can feel love or other intense feelings the way they did before. Accordingly, patients often actively avoid stimuli that precipitate recollections of the trauma and demonstrate a resulting increase in vigilance, arousal and startle response. Military combats, accidents, crime, abuse, assault, torture, divorce, bombings, fires, beatings- these experiences can lead to post-traumatic stress disorder, in which the sufferer relieves the event over & over to devastating effect, sometimes many years after the incident. The World Health Organization estimates that 20 percent of people exposed to a disaster show some kind of mild or moderate mental disorder soon after the event, with the number dropping to about 15 percent within a year, 3-4 percent will experience more severe problems.

The Effect on Memory

When humans take in new information- whether it’s a phone number, or seeing someone killed- the memory is “labile” at first, or chemically unstable. But at some point within the next six hours, a flood of proteins produced by the brain moves the memory from short-term to long-term imprint. The brain’s wiring changes each time something goes into long-term memory, but not all memories are equal. “You remember the day of your wedding better than three Tuesdays ago when there was nothing important going on.” Emotional memories activate a second process that ups their intensity. This is called a “gain switch”. With PTSD, this gain switch just gets turned way up after trauma. So now what happens is that people are just overwhelmed by their emotional memories. Studies have shown that emotionally arousing events cause stress-related hormones such as adrenaline to be released by the brain’s amygdale, which is involved in emotional learning and memory. PTSD may develop when the event is so emotionally powerful, and so much adrenalin is released, that the “gain-switch” is set too high. Then, each time the traumatic experience is recalled; the amygdale releases yet more hormones and intensifies the stressful memories even more.